Year	Percent
1970	0.89939
1971	0.09004
1972	0.89446
1973	0.66543
1974	0.71498
1975	0.20029
1976	0.0633
1977	-0.11733
1978	-0.13777
1979	-0.19002
1980	-0.01954
1981	-0.02225
1982	-0.00255
1983	0.10565
1984	0.29155
1985	-0.0063
1986	0.4309
1987	0.13525
1988	0.11914
1989	0.51305
1990	0.72651
1991	0.51566
1992	0.69871
1993	0.45558
1994	0.19241
1995	0.30729
1996	0.25436
1997	0.39499
1998	0.44495
1999	1.57055
2000	2.13924
2001	2.05448
2002	0.33343
2003	0.23518
2004	1.21246
2005	1.00195
2006	5.13997
2007	10.22633
2008	11.57866
2009	14.81979
2010	9.95127
2011	7.81589
2012	7.84655
2013	5.19015
2014	4.85774
2015	2.52596
2016	4.51061
2017	3.12084